Plastic article or earthenware shaping or treating: apparatus – With apparatus assembly or dismantling means or with idle part – Means permitting removal or substitution of elements during...
Reexamination Certificate
2000-07-26
2003-03-04
Silbaugh, Jan H. (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
With apparatus assembly or dismantling means or with idle part
Means permitting removal or substitution of elements during...
C425S193000, C425S412000, C425S422000, C425SDIG001, C264S003100
Reexamination Certificate
active
06527535
ABSTRACT:
STATEMENT OF GOVERNMENT INTEREST
The invention described herein may be manufactured and used by or for the Government of the United States of America for government purposes without the payment of any royalties therefor.
BACKGROUND OF THE INVENTION
The invention relates in general to manual die sets for pressing explosive powder and in particular to manual die sets for pressing explosive powder into hollow cylindrical pellets.
Manual die sets for pressing explosive powder into hollow cylindrical pellets are known. The explosive powder is a highly sensitive explosive molding powder, for example, PBXN-9 or PBXW-11. The manual die set, in combination with a press for supplying the pressing force, presses the explosive powder into hollow cylindrical (donut-shaped) pellets.
FIG. 1
is an elevation view, partially in cross-section, of a known manual die set
10
in a press configuration.
FIG. 2
is an elevation view, partially in cross-section, of the die set
10
in a first knockout configuration.
FIG. 3
is an elevation view, partially in cross-section, of the die set
10
in a second knockout configuration.
Referring to
FIG. 1
, manual die set
10
is used to press highly sensitive explosive molding powder into a hollow cylindrical pressed pellet
24
in the following manner. First, the baseplate
22
is fitted into the opening
20
in the bottom of the die
18
. A mandrel
16
is inserted in the die opening
20
and into the opening
26
in the baseplate
22
. The required amount of molding powder is poured into the die opening
20
. Next, the ram
12
with opening
14
is inserted into the top of the die opening
20
and mandrel
16
is inserted into opening
14
in the ram. Pressing force is applied by a press (not shown) to the top of ram
12
until the pellet
24
is formed.
Referring to
FIG. 2
, the die set
10
is manually turned upside down and placed on a first or mandrel knockout ring
28
. An ejector guide
30
having an opening
31
therein is placed on top of baseplate
22
and die
18
. A mandrel ejector
32
is inserted in the opening
31
in the ejector guide
30
. Pressing force is applied by a press to the top of mandrel ejector
32
so that the mandrel ejector
32
moves downwardly to force the mandrel
16
out of the die set
10
. Mandrel ejector
32
and ejector guide
30
are then removed.
Referring to
FIG. 3
, the manual die set
10
is removed from the mandrel knockout ring
28
of
FIG. 2
, again turned upside down and then placed on a second or pellet knockout ring
34
. Pressing force is applied by a press to the top of ram
14
. Ram
14
moves downwardly, ejecting the baseplate
22
(if not already removed manually) and the explosive pellet
24
. Ram
14
stops when it contacts the top of die
18
.
The process described above requires many time-consuming steps. Die set
10
must be turned upside down twice with the explosive pellet contained therein. The manual die set
10
also includes many pieces of tooling. Only well experienced technicians can handle the die set
10
, because of safety concerns associated with turning the die set upside down twice with the explosive pellet therein. Thus, a need exists for a manual die set that overcomes the problems of the manual die set of
FIGS. 1-3
.
SUMMARY OF THE INVENTION
In one embodiment, the present invention provides a manual die set comprising a ram, the ram defining a bore therethrough; a die, the die defining a bore therethrough for reciprocably receiving the ram; a baseplate having an upper portion and a lower portion and defining a bore therethrough, the upper portion of the baseplate being disposed in a bottom of the die bore, the lower portion of the baseplate supporting the die; a knockout ring for supporting the die; a supporting block disposed in an interior of the knockout ring, for supporting the baseplate when the manual die set is in a pressing configuration, the supporting block defining a bore therethrough; and a mandrel, the mandrel being disposed in the ram bore, the baseplate bore and the supporting block bore when the manual die set is in a pressing configuration, the mandrel including an upper large diameter portion, a transition portion and a lower small diameter portion.
Preferably, a diameter of the upper large diameter portion of the mandrel is about 0.050 inches larger than a diameter of the lower small diameter portion of the mandrel. More preferably, the transition portion of the mandrel is disposed in the baseplate bore in the lower portion of the baseplate, when the manual die set is in a pressing configuration.
The manual die set further comprises explosive molding powder disposed in the die bore between the ram and the upper portion of the baseplate, when the manual die set is in a pressing configuration.
The supporting block includes a channel extending from the supporting block bore to an outer surface of the supporting block, the channel having a width at least as large as a diameter of the supporting block bore. The knockout ring includes an opening having a width greater than a diameter of the supporting block such that the supporting block is removable from the interior of the knockout ring via the opening in the knockout ring.
In a preferred embodiment, the ram includes an opening in a top portion thereof, the manual die set further comprising an air cap disposed in the opening in the top portion of the ram, the air cap including a passage therein for air flow from the ram bore, the air cap defining a groove formed therein, the manual die set further comprising an O-ring disposed in the groove in the air cap. The ram includes at least one air passage in a lower portion thereof, the at least one air passage extending from the ram bore to an external surface of the ram.
The supporting block includes a second channel formed in a bottom portion thereof, the second channel extending from a point beyond the supporting block bore, in a direction opposite from a direction of the first channel, to the outer surface of the supporting block.
The lower small diameter portion of the mandrel includes an undercut formed therein, the undercut being located in the second channel of the supporting block, the manual die set further comprising a lock which is removably inserted in the second channel to engage the undercut in the mandrel thereby preventing vertical motion of the mandrel.
Another aspect of the invention is a method of pressing hollow cylindrical pellets comprising pouring explosive molding powder into a die bore; pressing a ram a first time to compress the explosive molding powder between the ram and a baseplate to form a pellet; removing a supporting block from the manual die set via an opening in a knockout ring; pressing the ram again to eject the pellet from the die; lifting the die from the knockout ring until a bottom of a mandrel is above the pellet; and removing the pellet from an interior of the knockout ring.
Further objects, features and advantages of the invention will become apparent from the following detailed description taken in conjunction with the following drawing.
REFERENCES:
patent: 3158547 (1964-11-01), Smith
patent: 3640654 (1972-02-01), Smith
patent: 3671164 (1972-06-01), Hara et al.
patent: 3790330 (1974-02-01), Roland
patent: 4157887 (1979-06-01), Sothje
patent: 4573895 (1986-03-01), DeSantis et al.
patent: 5039292 (1991-08-01), Taniwaga
patent: 5277570 (1994-01-01), Siggers
patent: 6261082 (2001-07-01), Han
Homer Mark
Nguyen Thu Khanh T.
Silbaugh Jan H.
The United States of America as represented by the Secretary of
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